nrf52 SPIM no MISO response

[Sergy]

Hi,

Im trying to connect MCP25625 via SPI on nrf52. I checked with the scope that CS, MOSI and SCK are correct, but I get no reply on MISO line whatsoever. I perform a very easy operation:

1. Reset - send 1 byte data
2. Read register - send 3 bytes.

Any ideas what to check? i have 2 custom boards and they both have the same issue.

OSC2 waveform

3-byte command bitbanging SCK and MOSI lines

[Sergy]

I figured it out with your help:) So here is what happened:

1. On one side the RESET pin of the device had to be connected to VCC if unused, so that was totally unrelated to nrf52 2) On the other side NRF52 cant send 1byte commands via SPI, and RESET command was a 1-byte command. I ended up bitbanging RESET command and using SPIM for the rest of longer commands. Thanks for the help!

[SRA]

I'm glad you figured it out, and that workaround Wojtek posted is really easy to follow, so I'd recommend rolling that in.